Is it any different than a piston engine?

Like, for an NA piston engine, you tune for ~14:1.

For a boosted piston engine, you tune to ~12.5:1.

Are rotarys the same, or they like a richer/leaner mixture compared to a piston engine?

 

Tubo rotatries are tuned much richer than those numbers..usually 11-11.4 seems to be what most people aim for.

 

Hmm, interesting. Is it because they make more power at that A/F level, or as an added measure of safety, to keep the Apex seals in one piece and in place?

 

More of a safety issue.

I'm sure they could make more power a little leaner...but we need to save our precious seals

 

It really depends on a number of factors, like compression ratio, boost pressure, intake temps, etc. But 11-11.5 is "relatively" safe when under 5 or more psi boost.

 

11.0 - 11.4 is too rich for 12 or less psi unless your IC is stock size.

I tune 12PSI for 11.8 and 11.4 for 14PSI. This is with almost stock ports.

 

Is that a "road" A/F ratio or on the dyno?

 

That is road in 4th gear.

Even though my ports are almost stock, I run a Blitz FMIC, upgraded fuel pump, upgraded ignition system, 1200cc secondary injectors, straight through exhaust, non-seq turbos, and all the other stuff that
adds longevity to the engine.

My engine has been extensively tested with the DATALOGIC and UEGO wideband in hot and cold weather.

My .dat file is on the DATALOGIT forum site as CHUCK2003*** something.

 

Chuck, thanks for the info.

In your experience, have your A/F ratios been richer on the dyno than on the street?